Test of Lorentz invariance using a continuously rotating optical resonator

Local Lorentz Invariance (LLI), stating that locally physical laws are identical in all inertial reference frames, constitutes the basis of special relativity and is an essential ingredient of both the standard model of particle physics and the theory of general relativity. A well known test experiment for this fundamental symmetry is the Michelson-Morley (MM) experiment (Fig. 1), which even predated the formulation of special relativity. First performed by A.A. Michelson in Potsdam in 1881 it was later repeated at increased precision together with E.W. Morley in Cleveland, Ohio, in 1887 [1]. While their motivation was to reveal an anisotropy of the speed of light c due to Earth's motion through an ether medium, that had been postulated as a carrier for electromagnetic waves, they were left with an unexpected null result. This was only clearly understood when Einstein formulated the theory of special relativity in 1905 building on the constancy of c, i.e. its independence on laboratory velocity and orientation. The latter has since been verified experimentally at improved precision by numerous repetitions of the MM-experiment (Fig. 2), providing a firm experimental basis for special relativity so far. © Springer 2006.